1. Field of the Invention
The present invention relates to artificial flows that change shape in response to changes in ambient conditions.
2. Prior Art Description
Artificial flowers, made from plastic, silk or other materials, are a well developed technology. They are beautiful, require little or no maintenance, and remain colorful year-round. However, while lifelike in appearance, compared to real flowers, they are static and do not grow or react to the environment. In particular, real flowers are known to bend towards the sun, bloom over time, and often close their buds at night or in the cold.
Inventors have addressed this discrepancy through a variety of mechanical means. One approach constructs the flower's leaves out of a material which bends when heated, and unbends when cooled. For example, Muir in 1951 (U.S. Pat. No. 2,561,217) patented a nightlight whose coarse petal-like strips were made from a laminate of metal and paper. When heated by a light bulb, the paper expands at a faster rate than the metal, forcing the lamination to curl away from the paper side. However, this material is also sensitive to humidity which also causes the paper to expand/shrink, and the foil can take a permanent crease during handling, causing the petal to no longer bend.
Other inventors, such as Elkins 2001 (U.S. Pat. No. 6,196,895) use a plastic film. In this case, rather than a lamination of two materials of different expansion coefficients, the material is stressed by dragging over a sharp edge. This mechanical stress causes one side of the film to have a different polymeric structure than the other. While simple, this stress can relax over time such that the film no longer reacts to heat.
Blonder U.S. Pat. No. 7,112,362 describes a laminate of two plastics with a specific difference in expansion coefficient. Unlike Muir and Elkins, this film is stable. Blonder discloses a number of applications for this material, including very simple blooming flowers, a thermometer, a temperature indicator for coffee cups, etc. For purposes of the application, we denote a flower made of a material that bends reproducibly when exposed to a change in temperature, as a “thermactive flower”, made from a “thermactive” lamination.
It is the object of this invention to improve on earlier uses for these temperature sensitive films, in particular, by employing those films in new and inventive flower applications, or by improving on a flower's function or realism.